Regional pattern of mercury wet deposition in Beijing

The regional pattern of mercury were deposition in Beijing was studied. The Hg concentrations in precipitation were detected in 0—0.83 ng/ml(summer) and in 0.371—1.73 ng/ml(winter), under extreme condition up to 3.4 ng/ml in heating periods. The sum of Hg wet deposition was 101.52 μg/(m 2·a) within Nov. 1994— Nov. 1995 and 123.09 μg/(m 2·a) within Nov. 1995 — Nov. 1996. The more precipitation fall down, the more Hg was removed from atmosphere, especially in heating periods. Burning coal for heating was thought as the reason of a baseline seasonable with highest Hg levels in winter. The Hg concentration in rainfall decreased with the raining duration, which clearly shows the efficiency of washouting Hg by wet deposition.

Effect of Mercury Deposition on Mercury Content and Distribution in Rye Grass

A grass (Italian rye grass) experiment with complete design of three factors (Hg, grass and exposure) andtwo levels (with and without the factor tested) was carried out in Goteborg, Sweden from May to September,1995, toward understanding the effect of mercury deposition on plant Hg conteot and its distribution. It hasbeen foulld that besides the two general pathways of Hg absorption, i.e. root uptake and foliar absorption,mercury deposition can also significantly increase Hg content and total load in grass plant. Such effectsseem to be condned only within the above-ground parts of grass plant. Estimate has been made to makeclear of the contributions of different pathways to Hg content and total Hg load in the upper part of grass.Results showed that the coDtribution of Hg deposition accounted for 27%-32% of Hg content in the above-ground parts of grass plant without adding Hg to the soil, decreasing with the increase of soil and/or air Hgconcentrations. The increment of Hg load in the upper part of grass plant caused by Hg deposition duringan interval of two weeks varied between O.o1~O.o7 pg pot-1, contributing to 17%~48% of the total Hg loadin grass plant exposed.

An assessment of variations in mercury deposition to Antarctica over the past 34,000 years

We performed a comparison analysis of the variations .in Mercury ( Hg) concentrations and the precipitation proxies ( e. g. , 18 O values and 10 Be concentrations) in the Dome C ice core. The results showed that there were significant correlations between Hg and δ 10O values, 10Be concentrations, indicating that the accumulation rate in Dome C is one of the key factors controlling the variations of Hg concentrations in the past 34 ,000 years, and implying that Hg concentrations in ice core can be used as another reliable proxy of precipitation rate in Antarctica. Based upon the high-resolution δ 18O values, we estimated the variations in mercury deposition flux to Antarctica over the past 34,000 years. The highest mercury deposition flux is about 3. 80 pg cm-2 yr-1 during the Last Glacial Maxium (LGM) as high as 3. 5 times of the mercury deposition flux ( about 1. 08 pg cm -2 yr -1) in Holocene due to the fluctuations in natural mercury emissions such as the oceanic biological emissions.

Increasing Anthropogenic Mercury Pollution over the Last 200 Years Revealed by Lagoonal Sediments from Hainan Island,South China

The toxic heavy metal mercury(Hg)has significantly enhanced the global Hg cycle influenced by human activities over the last century.In this study,we presented a high-resolution Hg deposition history between∼1780 and 2015 AD in a sediment core from Xincun Lagoon,located in the southeastern Hainan Island,South China,and analyzed it in conjunction with geochemical elements,grain-size distribution,organic matter,and HYSPLIT backward trajectory simulation.The objective was to investigate the influencing factors affecting historical Hg deposition in relatively remote regions and assess the extent of the effects of natural background and human activities.The results showed that the Hg in the sediment was deposited primarily through atmospheric deposition,which was closely related to regional and even global human activities.Anthropogenic Hg contamination increased gradually from the 1830s to 1850s,possibly due to Hg emissions from Opium Wars I and II occurring in southeastern China.High broad peaks of anthropogenic Hg were observed during the 1910s to 1950s and in the 1980s,likely associated with the two world wars and modern Chinese wars.In addition,a further sharp increase in anthropogenic Hg from the mid-1970s to the present occurred,likely originating from the intense industrial activities in China triggered by the reform and opening-up policy of China in 1978 and some countries in Southeast Asia.

临安区西径山不同森林中的汞迁移及沉降

森林系统,是汞在地球生物化学过程中极为重要的一环。其中,叶片是大气汞与森林交互作用的主要界面。本文以临安地区的典型落叶林、针叶林为例,进行定点监测,探明不同季节落叶林、针叶林中汞在叶片和林下土壤中的分布状况及其影响因素。定点监测实验的结果表明,森林汞在垂直方向上具有明显的分层累积现象,其中土壤中汞浓度最高,含量最多,凋落物其次,新鲜叶最低。且阔叶林在各垂直分层中汞含量均显著高于针叶林。2种森林类型汞均在7—9月达到峰值,这与森林生长发育的季节性与夏季土壤汞的再释放相关。凋落物汞输入是森林土壤汞的主要来源之一,而由土壤所固持的汞主要集中于0~10 cm土层,这与0~10 cm土层中含有的大量具有吸附、固定汞能力的有机质相关。另外,对阔叶林与针叶林的沉降通量估算结果显示,阔叶林沉降通量高于针叶林,这与阔叶林凋落物沉降通量显著高于针叶林相关。本研究的结果有助于了解森林叶片汞浓度以及土壤汞负荷的影响,以及不同季节森林叶片汞和土壤汞时空分布状况。同时,本研究也有利于进一步探明浙江省森林汞地球生物化学循环过程的特征与分布情况。

天山冰川退缩区土壤汞分布特征及累积

本文以新疆天山乌鲁木齐河源一号冰川退缩区为研究区域,通过^(210)Pbex、^(137)Cs放射性同位素测年和侵蚀性堆积地貌判定退缩区的年代演替序列,并据此设置了系列采样点,对土壤进行分层采样,测定样品总汞浓度等指标,计算各年代退缩区的汞累积速率,探究乌鲁木齐河源一号冰川退缩区土壤中汞的分布特征及其累积过程.结果表明:冰川退缩区土壤汞含量和汞储量随着退缩时间增长呈现出增加的趋势,各层土壤汞的平均含量由大到小依次为:0~5cm[(13.28±6.60)μg/kg]>5~10cm[(11.47±7.34)μg/kg]>10~15cm[(10.19±6.57)μg/kg]>基岩[(0.23±0.09)μg/kg];冰川退缩区植被生长促进了土壤汞的富集,退缩区内土壤汞浓度与土壤有机碳、氮含量呈显著正相关,而且由于植被生物量很小,退缩区土壤中汞的累积速率也较低(0.09~33.43μg/(m^(2)·a),平均值为16.92μg/(m^(2)·a));近250a来(1777年以来),天山一号冰川退缩区土壤汞累积速率呈加速增加趋势,由1777年的0.09μg/(m^(2)·a)增加至2017年的33.43μg/(m^(2)·a),这意味着自工业革命以来大气汞含量及沉积量在不断增加.

海洋汞同位素的研究范式及最新进展

汞(Hg)是一种具有生物毒性且能够全球传输的重金属元素,在海洋环境中易转化为神经毒素甲基汞并沿食物网进行富集和放大,危害生态系统和人类健康。准确约束海洋汞的来源、迁移与转化是理解海洋汞循环的关键,对更新现有海洋汞循环模型和制定相关环境政策具有重要价值。近十多年发展起来的汞稳定同位素技术为研究环境中的汞循环以及生态环境效应开辟了新视野。汞同位素独特的“三维”分馏模式,特别是非质量分馏(MIF),为研究海洋汞循环带来了科学范式的改变,取得了一系列重要发现。本文从海洋汞的来源以及甲基汞的生成、迁移与转化两大方面的应用系统阐述了近十多年来汞同位素体系在示踪海洋汞循环方面的主要进展,重点剖析了汞同位素在远洋大气汞沉降途径以及甲基汞循环方面的应用等近期研究热点。未来需结合更精细的汞同位素测试手段以及汞同位素分馏控制实验进一步明确海洋汞同位素分馏的主要控制因素,拓展汞同位素的应用空间。

Multiple metal sources in polymetallic W-Sn ore deposits revealed by mercury stable isotopes

Granite-related W-Sn ore systems are commonly associated with coeval Pb-Zn mineralization. It remains unclear whether these metals are derived from the same sources or not. Mercury(Hg) is a common minor component in such systems. Hg isotopes undergo unique mass-independent fractionation(expressed as Δ^(199)Hg values), which is mainly generated during Hg photochemical reactions on Earth's surface and not affected by magmatic-hydrothermal processes, offering an excellent opportunity to trace metal sources in hydrothermal systems. We observed near-zero Δ^(199)Hg values in wolframite(-0.10‰ to0.08‰, n=11), and in skarn-(-0.17‰ to 0.12‰, n=48) and greisen-type(-0.12‰ to 0.10‰, n=11) bulk tin-tungsten ore from eight major ore deposits in South China. These values are identical to those of coeval highly evolved granites(-0.13‰ to 0.12‰,n=49), supporting that Hg in W-Sn ores were sourced from granite. However, sulfides(e.g., pyrite, chalcopyrite, arsenopyrite,galena, and sphalerite) in these deposits exhibit negative to near-zero Δ^(199)Hg values(-0.42‰ to 0.09‰, n=124), which indicates a contribution of Hg and by inference other metals from both Precambrian basement rocks(Δ^(199)Hg<0) and ore-related granites.The study demonstrates that multiple sources of metals were involved in the formation of the polymetallic W-Sn deposits, and further highlights that extraction of metals from basement rocks may be a critical control on the formation of economically important mineralization of base metal sulfides(e.g., Pb, Zn) in granite-related magmatic-hydrothermal systems.

Atmospheric particle-bound mercury in the northern Indo-Gangetic Plain region:Insights into sources from mercury isotope analysis and influencing factors

Lumbini is a world heritage site located in the southern plains region of Nepal, and is regarded as a potential site for evaluating transboundary air pollution due to its proximity to the border with India. In this study, 82 aerosol samples were collected between April 2013 and July 2014 to investigate the levels of particulate-bound mercury(PBM) and the corresponding seasonality, sources, and influencing factors.The PBM concentration in total suspended particulate(TSP) matter ranged from 6.8 pg m^(-3) to351.7 pg m^(-3)(mean of 99.7 ± 92.6 pg m^(-3)), which exceeded the ranges reported for remote and rural sites worldwide. The Hg content(PBM/TSP) ranged from 68.2 ng g^(-1) to 1744.8 ng g^(-1)(mean of 446.9 ±312.7 ng g^(-1)), indicating anthropogenic enrichment. The PBM levels were higher in the dry season(i.e.,winter and the pre-monsoon period) than in the wet season(i.e., the monsoon period). In addition, the δ^(202) Hg signature indicated that waste/coal burning and traffic were the major sources of Hg in Lumbini during the pre-monsoon period. Meanwhile, precipitation occurring during photochemical processes in the atmosphere may have been responsible for the observed Δ^(199) Hg values in the aerosol samples obtained during the monsoon period. The PBM concentration was influenced mostly by the resuspension of polluted dust during dry periods and crop residue burning during the post-monsoon period. The estimated PBM deposition flux at Lumbini was 15.7 lg m^(-2) yr^(-1). This study provides a reference dataset of atmospheric PBM over a year, which can be useful for understanding the geochemical cycling of Hg in this region of limited data.

Elevated Mercury in Ambient Air and Soils Impacts of Historical Air Emissions (1897-1991) from a Chlor-Alkali Plant (CAP)

Mercury contamination was found to be widespread in soils at a property in Upstate New York. Historical site use suggested that the mercury did not result from prior industrial use of the property. Soil contamination may have resulted from atmospheric deposition of mercury released from properties in close proximity to the contaminated property. The purpose of this forensics investigation was to examine to what extent atmospheric deposition of elemental mercury may have influenced mercury levels found in surficial soils on the contaminated property and further to identify the source(s) of the mercury. Work efforts included an examination of historical records available for a chlor-alkali plant (CAP) upwind of the contaminated property to establish historical use and disposal practices for elemental mercury. Mercury emissions test data from the Upstate New York chlor-alkali facility were modeled (USEPA ISC3) as a means of estimating impacts on ambient air and soils vicinal to the facility. Mercury emissions from the facility were modeled as both a point source and volume source. For example, at a location 305 meters to the east and 30 meters to the north of the modeled source centerline elemental mercury concentrations in ambient air were estimated at 270 ng/m3 (average results based upon 5 years of meteorological data). This value is contrasted to a background concentration of 1.6 ng/m3 (USEPA Report to Congress 1997). As a result of the modeling data in combination with findings related to mercury use and disposal practices at the NY CAP documented from the records review, it was concluded that emissions from the CAP facility during the period of operation (1897-1991) most likely accounted for the concentrations of elemental mercury found in surficial soils at properties situated downwind of the CAP. These findings were further corroborated by information available in the open literature for CAPs world-wide.

Geochemistry of Mercury Mineralization, Catian, West Hunan

The Tongfeng mercury zone is an important producer of mercury in China.The underlying Lower Cambrian black rock series is strongly depleted in mercury and is thought to be the major source bed for mercury mineralization .The Catian deposit ,as the representative of the zone, was formed at low temperature,which is characterized by a meteoric chlorine-rich and sulfur-poor ore-forming solution of high salinity.A geochemical genetic model of buried hydrothermal explosion is proposed.

近4万年来雷州半岛北部地区汞沉积及其影响机制

雷州半岛地处热带北缘,受东亚季风影响强烈。以取自雷州半岛北部下录地区的埋藏泥炭沉积作为研究材料,测试分析了该岩心的汞浓度及其分布情况,将测试结果与其他气候环境代用指标如孢粉、炭屑、烧失量(LOI)以及有机碳同位素(δ^(13)C_(org))等进行对比分析,讨论自MIS(Marine Isotope Stages)-3晚期(约40 cal ka B.P.)至全新世早期(约6.9 cal ka B.P.)区域气候与环境变化影响下的汞沉积过程及可能的影响机制。结果显示:近4万年以来,沉积物的汞浓度与乔木类孢粉浓度的变化较吻合,两者之间显示出较高的相关性,揭示了晚更新世晚期以来,森林群落作为重要的地表汞库,在地区汞沉积过程中起到固定、储存和传输作用。此外,汞浓度与岩心中炭屑沉积通量(指示了区域性野火发生状况)的变化存在相反趋势,反映了区域性野火活动对地表植被以及土壤有机质的焚毁破坏,造成地表汞向大气的释放,不利于汞在地表和沉积物中的沉积与保存。对比不同区域的汞沉积记录发现,晚更新世晚期以来,下录泥炭汞浓度记录与全球其他地区汞记录、粉尘记录等具有较高的相似度,特别是MIS-2时期均存在明显峰值,反映了全球气候变化影响下,大气粉尘沉降对地表汞的输送和沉积具有较大贡献。

烃汞气体测量法在中非沉积型铜矿的找矿可行性研究

沉积型铜矿是中非铜—钴成矿带最主要的铜(钴)成矿类型,为提高该类矿床的找矿效果,在刚果(金)马本德—利卡西一带开展烃汞气体测量法找矿可行性研究。试验结果表明,在两处已知矿体上均有较好的烃汞多指标异常显示,但异常分布位置受控于矿体的产状,据此总结了烃汞气体异常模式,并初步探讨其成因;在该地区开展了隐伏铜(钴)矿找矿预测,圈定的找矿有利靶区经钻探验证发现了一处工业铜矿体,取得了一定的找矿效果。

辽宁阜新排山楼金矿床深穿透地球化学找矿方法的应用研究

排山楼金矿床位于辽宁阜新,是目前中国发现最大的受韧性剪切带控制的糜棱岩型金矿床之一。矿体赋存于太古宇建平群蚀变糜棱岩破碎带内,矿石蚀变强烈,品位偏低。目前,该矿床经多年开采已步入危机矿山行列,迫切需要开展接替资源勘查工作,增加矿石储量,延长服务年限。应用深穿透地球化学找矿方法对排山楼金矿床进行成矿预测研究,主要包括有机烃类气体测量、吸附相态汞测量和氡气测量地球化学方法。通过布设2条剖面,采集土壤地球化学样品73件,每件样品分析测试吸附相态汞及7种有机烃类气体组分,并对36勘探线开展氡气测量研究。研究结果表明,甲烷、乙烷、丙烯、正丁烷和吸附相态汞剖面异常与矿体均有较好的空间对应关系,甲烷、乙烷在矿体上方呈单峰式剖面异常;丙烯、正丁烷和吸附相态汞为多峰式异常。最后,通过对烃、汞剖面异常特征的综合对比分析,圈定出4处成矿靶区。

北京市区及郊区大气中的汞沉降的估算

以Throughfall法估算出北京市 1996年大气汞干沉降率为 5 2 8.88μg·m2 ·a-1,以沉降速率估算出 1998年北京市汞的年沉降量为 6 87.5 μg·m-2 ·a-1.

土壤挥发性汞释放通量的研究

在总结前人工作的基础上，建立了一套野外现场测量土壤挥发性汞释放通量的实验装置，于１９９３－０８至１９９３－１０在贵州省三类地区（高汞区、人为乘污染区和背景参考区）的５个采样点进行土壤挥发性汞释放通量的研究。结果表明．土壤挥发性汞释放通量具有白天高于夜间的昼夜变化规律；土壤挥发性汞释放通量与土壤总汞含量、大气气温相关。

采选矿活动对铅锌矿区水体中重金属污染研究

以湘西境内凤凰铅锌矿区不同区域的地表水为对象,研究了铅锌矿区水体中Pb、Zn、Hg等元素的污染状况及成因。结果表明,凤凰铅锌矿区内地表水受到重金属复合污染,其中水Pb严重污染,水Zn轻度污染,水Hg中度污染。矿区地表水中Pb、Zn、Hg平均含量分别为(0.145±0.060)mg·L-1(、0.362±0.393)mg·L-1和(0.175±0.359)!g·L-1,与地表水环境质量国家标准(GB3828-2002)相比,矿区水Pb平均含量超过国标Ⅳ类水质量标准2.9倍,Zn基本符合国家Ⅲ类水水质标准,Hg超过国标Ⅲ类水质量标准1.75倍。溪流水体自净作用对水质重金属污染具有一定的修复能力,该能力受距污染源的距离、流程长度以及水质污染程度的影响。水体中Pb、Zn、Hg的含量受原生地球化学环境的控制,同时,表生地球化学作用和人为采选矿活动也深刻影响它们在水体中的分布。

重庆市汞污染的观测研究

为研究重庆市区汞污染状况，2004年9～11月，同步观测了重庆市近郊铁山坪小流域（TSP）和观音桥（GYQ）两个区域的全沉降、穿透水、地表径流和土壤中的总汞含量，估算了小流域中汞的输入输出通量，分析了城区和郊区的大气汞沉降和分布特征。结果表明，重庆已在一定程度上受到汞污染。在TSP，湿沉降是汞输入的主要方式，也就是说，在TSP，细颗粒是大气汞的主要来源，表层土则是大气汞的一个主要的汇。GYQ区域的汞污染比TSP相对严重。在GYQ，除了湿沉降以外，干沉降是汞来源的重要形式，表明在GYQ，粗颗粒可能对大气汞有很大的贡献。因此，本地源的排放对城区的影响比对郊区的影响大，尤其是城区火电站附近的土壤样品比郊区土壤的汞含量高很多，说明火电站是大气汞的重要来源之一。

贵州丹寨汞矿田甲烷包裹体研究及其地质意义

根据显微镜下观察和包裹体均一温度测定,在丹寨汞矿田中发现了大量高密度甲烷包裹体,其均一温度为-92.7～-118.2℃,密度为0.278～0.350g/cm3。与甲烷包裹体共生的盐水包裹体均一温度主要为170～230℃。以盐水包裹体的均一温度作为甲烷包裹体的捕获温度,用包裹体热力学方法计算出高密度甲烷包裹体在成矿过程中的捕获压力高达106.8～233.3MPa。高密度甲烷包裹体的发现,为丹寨古油藏中原油在深埋过程中受高温裂解作用产生超压环境提供了重要证据。甲烷包裹体的观测结果为研究油热裂解气藏的压力条件和探讨汞成矿与油气成藏之间的关系提供了重要信息。

青海省苦海汞(金)矿床地质特征及找矿前景分析

为查明本区成矿地质特征及综合评价其找矿潜力,通过野外地质调查和室内各类测试分析研究,表明苦海汞(金)矿床位于东昆南造山带南带,其矿体受构造和地层联合控制,呈透镜状、似层状平行产出,矿化边界性较好;矿石矿物以低温矿物组合为主,矿石组构较为单一;围岩蚀变主要为硅化、碳酸盐化;成矿流体为低温流体,同时有深部热液参与成矿的显示,属造山型金矿系列矿床之一。在此基础上通过对区域成矿条件及区域矿床成矿特征综合对比分析,认为苦海汞(金)矿区剥蚀深度较小,保存条件较好,具有很大的造山型金及多金属矿床找矿远景。